In Germany, if you are unemployed and looking for a job (or for state benefits) you can always turn to the nearest “Agentur für Arbeit,” or federal employment agency. The city of Oberhausen, in the highly urbanized Ruhr region, knows a lot about unemployment and skill enhancement—it’s been navigating post-industrial, post-coal economic shifts for several decades. So when the need for a new employment center in the inner city arose in 2014, city officials set out to find a way to kill three birds with one stone: offer new job opportunities in an attractive new facility, placing it in a central location adjacent to the central Altmarkt (Old Market), and top the new structure with a greenhouse as research unit for the local university. A public architectural competition was organized in 2016 and was won by architects Kuehn Malvezzi and landscape architects Atelier le Balto—both based in Berlin.

The design team proposed to add another element: a vertical garden to connect the public square with the roof. The route, along a light aluminum stair, now leads from the lime tree–lined market square past a series of platforms and various climbing plants (such as chocolate vine and Himalayan clematis), through a small area, and up to the rooftop greenhouse and terrace, with views over the historic city center. The structure’s brick facade echoes those in the city, but goes further, says architect Wilfried Kuehn: “We reveal the brick cladding consciously as a facade instead of giving the impression of being solid. The stacked bond brickwork produces an a-tectonic visual appearance.”

Well, the five-story building still looks pretty solid, with the lightweight greenhouse further evincing its sturdiness. For the interiors, the architects created a “warehouse typology,” with floor-to-ceiling windows, exposed concrete beams, and raw, adaptable open spaces.

Outside, the disparate functions are easily discernible, but aesthetically connected. Strong, horizontal lines of galvanized steel run along the brick facade and continue into the metal trellis of the vertical garden staircase and windows, forming a grid that continues into the glass walls of the greenhouse above.

The greenhouse, by the way, is not technically public, though you can join regular tours of the building. Rather, it’s run by Oberhausen’s Fraunhofer Institute for Environmental, Safety, and Energy Technology with the aim to explore possibilities of building-integrated agriculture. In three differently climatized areas, workers test and development a wide range of food production technologies: ebb and flow systems, water basins, pyramid-like grow beds, and rolling plant tables. “The greenhouse uses the integration of building services, so that the functions benefit each other,” says Kuehn. “For instance, the waste heat and CO2 removed from the offices now enhances plant growth in the greenhouse. Rainwater from the roof is used to water the plants, while graywater is partly used for flushing the toilets.”

And Oberhausen residents benefit too, and not just if they are looking for a job: Some of the greenhouse’s crops can be found six days a week, on sale at the fresh produce market in the Altmarkt just below.